1. Field of the Invention
The present invention pertains to rotary pumps and more particularly to gear pumps.
2. Description of the Related Art
Rotary pumps have been developed for a number of different uses, ranging from fire engine apparatus to volumetric dosing of commercially important materials. Rotary pumps may be classified according to structural features of their material propelling elements. One commercially important type of rotary pump is the gear pump, in which one or more pairs of intermeshing gears propel material with their gear teeth. Examples of these types of pumps are given in U.S. Pat. Nos. 1,005,586; 2,176,322; 3,096,719; 3,427,984; 2,967,487, and in a modified, related form in U.S. Pat. Nos. 3,170,408; 3,171,590; and 4,787,831.
Pumps of the above-described type can be employed with a single shaft, with the gear teeth in contact with an appropriately shaped casing, to trap the material to be transported between the gear and the casing. Pumps may also employ a pair of intermeshing gears designed to propel materials between intermeshed teeth. Pumps may be distinguished by the configuration of the gears and may, for example, utilize spur gears as well as screw-type or helical gears.
Regardless of the types of gears employed, design challenges have arisen to minimize leakage of material flowing through the pumps while providing adequate rotational support for the shafts on which the gears are mounted. These and other improvements in gear pumps are constantly being sought. For example, it is desirable in some applications to be able to clean a pump "in place" without requiring the pump to be removed and disassembled at a remote cleaning location.